Correct option is=A
because 25mph means=25miles per hour
Refer to the diagram shown below.
μ = the coefficient of dynamic friction between the crate and the ramp.
1. The applied force of F acts over a distance, d.
The work done is F*d.
2. The component of the weight of the crate acting down the ramp is
mg sin(30) = 0.5mg.
The work done by this force is 0.5mgd.
3. The normal force is N = mgcos(30) = 0.866mg.
This force is perpendicular to the ramp, therefore the work done is zero.
4. The frictional force is μN = μmgcos(30) = 0.866μmg.
The work done by the frictional force is 0.866μmgd.
5. The total force acting on the crate up the ramp is
F - mgsin(30) - μmgcos(30) = F - mg(0.5 - 0.866μ)
6. The work done on the crate by the total force is
d*(F - 0.5mg - 0.866μmg)
Using the average velocity formula which is total distance divided by total time. If the distance is given in km convert to m then divide by 1000 to get m and if time is given in minutes then divide by 60 to get seconds. And after converting, divide to get your final answer in m/s. Hope that helped!
Scientists say that it is hard to track how monarch butterflies migrate
Answer:
2 or 3
Explanation:
2 or 3 look exactly the same to me.